Uncharted 4 did 8.7m on its first 9 months, so GoW doing 5m on its first 3, and outside of holidays, is not something easy or guaranteed. But I'm pretty confident it will too.
No, Uncharted did 8.7m in ~7.5 months. It released May 10 and was at 8.7m at the end of 2016.
It also did 2.7 million week one.
When the herd loses its way, the shepard must kill the bull that leads them astray.